应用固相萃取(SPE)及液相色谱-串联质谱(LC-MS/MS)技术,建立了水中痕量(ng/L)四环素类、磺胺类、大环内酯类、喹诺酮类和β-内酰胺类5类共19种抗生素的同时定量检测方法。水样通过HLB萃取小柱富集后,以C18反相色谱柱为分析柱,乙腈-0.1%甲酸溶液为流动相,采用LC-MS/MS进行定量分析。选择电喷雾正电离源(ESI+),多反应监测模式(MRM),内标法定量。19种抗生素在0.5-1 000μg/L范围内均具有良好的线性关系,方法的定量下限(S/N=10,1 000倍浓缩)为0.1-0.5 ng/L。以纯水和河水(黄浦江水)作为基底,13C-咖啡因为内标物,加标质量浓度为20、100 ng/L时,抗生素的平均加标回收率分别为75%-125%和77%-132%,相对标准偏差(RSD)分别为1.7%-6.9%和0.9%-6.5%,表明所建立的测试方法准确可靠。研究结果表明,黄浦江水受到了抗生素污染,共检出15种抗生素,检出的四环素类、磺胺类、大环内酯类、喹诺酮类及β-内酰胺类抗生素污染质量浓度分别为13.0-56.9、12.2-103.4、53.8-84.8、3.1-26.2、16.5-181.6 ng/L。
A solid phase extraction and liquid chromatography coupled with tandem mass spectrometric(SPE/LC-MS/MS) method was established for the simultaneous determination of 19 antibiotics,including tetracyclines,sulfonamides,macrolides,quinolones and β-lactam antibiotics,in water samples up to the concentration range of ng/L level.13C-caffeine was selected as the internal standard.Samples were acidified and extracted through a hydrophilic-lipophilic balance(HLB) cartridge.The extract was separated on a reverse phase column using methanol-0.1% formic acid as mobile phase.The antibiotics were quantified with the internal standard method under multiple reactions monitoring(MRM) mode with an orthogonal electrospray ionization source(ESI+).The SPE conditions and LC-MS/MS parameters were optimized.Under the optimized conditions,the calibration curves of 19 antibiotics were linear in the range of 0.5-1 000 μg/L with limits of quantitation(S/N=10,concentrated by 1 000 fold) of 0.1-0.5 ng/L.The mean recoveries of 19 antibiotics from water matrices at two spiked level of 20 ng/L and 100 ng/L were in the ranges of 75%-125% and 77%-132%,with relative standard deviations of 1.7%-6.9% and 0.9%-6.5%,respectively.The results also showed that the Huangpu River was polluted by antibiotics,in which fifteen antibiotics were detected with the concentrations of 13.0-56.9 ng/L for tetracyclines,12.2-103.4 ng/L for sulfonamides,53.8-84.8 ng/L for macrolides,3.1-26.2 ng/L for quinolones and 16.5-181.6 ng/L for β-lactams,respectively.